Direct fixation rail fastener

ABSTRACT

The track of a rapid transit rail system is fastened to a supporting structure via the intermediary of a plurality of rail fasteners. Each rail fastener includes a track plate supported from a base plate via the intermediary of an elastomer layer bonded between the plates. A pattern of voids is provided in the elastomer to enhance the vibration damping effect of the elastomer layer. Increased lateral restraint for the track plate and rail is provided by means of a pair of tubular members upstanding from the base plate on opposite sides of the rail. High compressive strength inserts are provided between the lateral side edges of the track plate and the upstanding tubular members for taking the lateral forces on the track plate in compression on the insert members.

United States Patent [191 Landis Jan. 8, 1974 [73] Assignee: The LandisSales Company, Los

Altos, Calif.

[22] Filed: Oct. 13, 1972 [21] Appl. No.: 297,318

Primary Examiner-Gerald M. Forlenza Assistant Examiner-Richard A.Bertsch Attorney-Harvey G. Lowhurst et a1.

[57] ABSTRACT The track of a rapid transit rail system is fastened to asupporting structure via the intermediary of a plurality of railfasteners. Each rail fastener includes a track plate supported from abase plate via the intermediary of an elastomer layer bonded between theplates. A pattern of voids is provided in the elastomer to enhance thevibration damping effect of the elastomer layer. Increased lateralrestraint for the track plate and rail is provided by means of a pair oftubular members upstanding from the base plate on opposite sides of therail. High compressive strength inserts are provided between the lateralside edges of the track plate and the upstanding tubular members fortaking the lateral forces on the track plate in compression on theinsert members.

[52] U.S. Cl 238/310, 238/282, 238/283, 238/304 [51] Int. Cl. Blb 9/62[58] Field of Search 238/287, 304, 282, 238/264, 283, 308, 374, 297

[ 5 6] References Cited UNlTED STATES PATENTS 2,719,676 10/1955 Prater238/283 3,387,781 6/1968 Moses et al 238/283 3,451,621 6/1969 DeSplinter 238/283 3,576,293 4/1971 Landis 238/310 3,581,990 6/1971 Kirik238/287 Q o e a d PATENTEU 8 SHEET 1 0F 2 IINU DIRECT FIXATION RAILFASTENER DESCRIPTION OF THE PRIOR ART Heretofore, rapid transit railsystems have been fastened to underlying support structures, as ofconcrete, via the intermediary of a plurality of rail fasteners. Theserail fasteners have included a track plate affixed to the rail and abase plate affixed to the supporting structure with an elastomer layerbonded in between the track plate and the base plate for dampingvibration of the track and for electrically insulating the track fromthe base structure. Lateral restraint for the rail has been provided bymeans of an upturned side lip of the base plate which restrained thelateral deflection of the track plate and, therefore, the rail viacompression of a thickness of the elastomer bonded in place between thelateral spaced longitudinal directed side edges of the track plate andthe upstanding lip portion of the base plate. Such a rail fastener isdisclosed and claimed in U. S. Pat. No. 3,576,293 issued Apr. 27, 1971and assigned to the same assignee as the present invention.

One of the problems encountered in this prior rail fastener is that whenthe elastomer layer is provided with voids for increasing the vibrationdamping effect of the rail fastener, some of the lateral restraintprovided by the bonded layer of elastomer material is removed, therebyplacing higher compressive loads on that portion of the elastomer layerinterposed between the upturned lip of the base plate and the lateralspaced side edges of the track plate. As a result, the compressiveforces on that portion of the elastomer intervening between the lip andthe lateral side edges of the track plate was excessive producingexcessive lateral deflection of the track plate and rail affixedthereto.

It is also known from the prior art that voids may be provided in theelastomer layer between the track plate and the base plate forincreasing the vibrational damping effect of the rail fastener. Such aprior rail fastener including a system of voids for vibration damping isdisclosed in U. S. Pat. No. 2,656,l 16 issued Oct. 20, 1953.

SUMMARY OF THE PRESENT INVENTION The principal object of the presentinvention is the provision of an improved direct fixation rail fastenerfor fastening a track to a support structure and for providingvibrational damping and electrical isolation between the track and thesupporting structure.

In one feature of the present invention, a lateral restraining structureis disposed upstanding from the base plate on opposite lateral sides ofthe track and a high compressive strength insert is interposed betweenthe adjacent edge of the track plate and the upstanding lateralrestraining structure for taking in compression and transferring lateralforces on the track plate to the upstanding lateral restraining means,whereby increased lateral restraint is obtained for the rail to preventexcessive lateral deflection thereof in use.

In another feature of the present invention, the lateral restrainingstructure includes a pair of tubular members upstanding from the baseplate on opposite sides of the track and means are provided for rigidlycoupling the upstanding tubular members to the base plate such that thetubular members may withstand substantial lateral force withoutexcessive deflection.

In another feature of the present invention, the tubular lateralrestraining members, upstanding from the base plate, are of rectangularor square cross-section and the track plate includes a pair of square orrectangular apertures coaxially aligned with the tubes. High compressivestrength inserts having a pair of rectillinear portions are interposedbetween the mutually opposed laterally spaced flat side edges of thetubes and the rectillinear side edges of the apertures in the trackplate, whereby the high compressive strength inserts can be uniformlyloaded for transferring the lateral restraining forces between the trackplate and the laterally restraining tubular members.

In another feature of the present invention, the elastomer layer isprovided with a plurality of elongated voids laterally directed of thetrack and spaced apart along the direction of the track with the baseplate being apertured in registration with each of said elongated voids.

Other features and advantages of the present invention will becomeapparent upon a perusal of the following specification taken inconnection with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a railand rail fastener assembly incorporating features of the presentinvention,

FIG. 2 is an enlarged plan view of the structure of FIG. 1,

FIG. 3 is a sectional view of the structure of FIG. 2 taken along line3-3 in the direction of the arrows,

FIG. 4 is a sectional view of the structure of FIG. 2 taken along line4-4 in the direction of the arrows,

FIG. 5 is a sectional view of the rail fastener portion of the structureof FIG. 2 taken along line 5-5 in the direction of the arrows, and

FIG. 6 is an enlarged perspective view of a portion of the structure ofFIG. 3 delineated by line 66.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to F IG. 1, thereis shown a rail fastener 1 of a type incorporating features of thepresent invention for fastening a rail 2 to a supporting structure 3,such as a concrete slab. The rail fastener l is an improvement of therail fastener disclosed and claimed in the aforecited US. Pat. No.3,576,293 and the disclosure in this patent is hereby incorporated byreference for a detailed description of the type of rail fastener ofwhich the present invention is an improvement.

Referring now to FIGS. 2 and 3, the rail fastener 1 will be described ingreater detail. The rail fastener 1 includes a base plate structure 4,as of M1 inch mild steel plate, disposed overlaying the concrete slab 3to which it is secured by means of a pair of bolts 5 disposed atopposite diagonal corners of the base plate 4. The bolts pass throughapertures 6 in the base plate 4 to threadably mate with a metallicinsert 7 anchored in the concrete slab 3. In a typical example, the baseplate 4 has a lateral width of approximately 14.5 inches and alongitudinal extent, parallel to the direction of the rail, ofapproximately 7.5 inches.

A track plate 8, as of -inch mild steel, is disposed overlaying the baseplate 4. An elastomer layer 9 is vulcanized (bonded) in place betweenthe base plate 4 and the track plate 8 to provide vibrational dampingfor the track plate and to electrically isolate the track plate 8 fromthe base plate 4. In a typical example, the elastomer layer 9 has athickness of 0.75 inches. A shimming polyethylene gasket or pad 11 isinterposed between the base plate 4 and the concrete slab 3 to toaccommodate vertical alignment of the rail 2.

A pair of rail clips 13 serve to clip the skirt portions of the bottomflange of the rail 2 to the track plate 8. The rail clips 13 aredisposed in diagonally offset relation on opposite sides of the rail 2.The rail clips 13 are bolted to the track plate means of two %-111Chbolts 14 passing through bores 15 in the clips 13 and tightened down bynuts 16 onto lock washers 17.

The rail 2 is laterally adjustable by lateral adjustment of thepositions of the rail clips 13. For this purpose, two laterally directedT slots 18 are provided in the track plate 8 and in the underlyingregion of the elastomer layer 9. The head portions 19 of the bolts 14ride in that portion of the slots 18 which extend into the elastomerlayer 9 such that the head of the bolt is caught on the lower lip of theT-slot in the track plate 8. An upper portion of the track plate whichis adjacent the T slot is provided with longitudinally directedserations at 21 to receive a gripping land portion 22 on the undersideof the rail clip 13 to prevent slipping of the rail clip relative to thetrack plate when the nuts 16 have been tightened. That portion of theT-slot 18 which extends into the elastomer layer 9 is opened to theadjacent front or rear'edge of the rail fastener 1 for irrigation of theT-slot to prevent accumulations of corrosive substances therein.

A plurality of laterally directed elongated voids 25 are provided in theelastomer layer 9 (see FIGS. 2 and 5) in the central region generallyunderlaying the rail 2. The voids serve to increase the compliance ofthe elastomer layer 9 for increasing the vibration damping effect of theelastomer layer 9. In a typical example, the voids 25 are approximatelythree-eights of an inch wide and 4 to 6 inches in length depending uponthe position of the slots. The slots extend through the base plate 4 andto within aproximately one-sixteenth of an inch of the bottom surface ofthe track plate 8. The slots 25 are spaced apart along the direction ofthe rail 2 by approximately 1 inch between center lines.

Some lateral restraint of the track plate 8 is obtained due to the shearforces generated by the bond between the elastomer layer 9 and the baseplate 4 and track plate 8, respectively. However, due to the provisionof the voids 25 substantial additional lateral restraint is desirable toprevent undue lateral deflection of the rail 2.

Accordingly, (See FIGS. 2-4) a pair of generally square apertures 27,provided in diagonal corners of the track plate 8,- coaxially surroundthe holddown bolts 5. The square apertures 27 are oriented withrectilinear sides parallel to the longitudinal axis of the rail 2.Square tubular spacers 28 are disposed coaxially of the bolts 5 with theflat sides of the square tubular spacers 28 being parallel to therectilinear sides of the openings 27 in the track plate 8.

A high compressive strength electrically insulative insert 29, as ofnylon, is coaxially interposed between the side walls of the apertures27 and the tubular spacer 28. The coaxial arrangement of the insert 29and tubular spacer 28 is shown in perspective view in FIG. 6. The insert29 includes a pair of longitudinally directed laterally spaced generallybar-shaped portions 31 interconnected by a pair of laterally directedrelatively thin web portions 32. The longitudinally directed barportions 31 serve to take laterally directed forces exerted on theinsert 29 in compression and to transmit those forces to the tubularspacer 28 which serves as the lateral restraining member. In a typicalexample, the tubular spacer 28 has an axial length of l and 19/32 inchesand is of square cross-section having a 3/ 1 6th inch wall thickness andbeing 1.5 inches on a side, and being made of mild steel. in a typicalexample, the insert 29 has a square inside aperture l.5 inches on a sidewith the depth of the insert being three-fourths of an inch and thelateral extent of each bar portion 31 being onehalf inch. The retainingwebs 32 are only a few thousandth of an inch thick.

A mild steel washer 35, as of 2.25 inch diameter with an inside holesize of l5/l6ths inch diameter and having a thickness of 0. l 65 inches,is captured between the upper end of the tubular spacer 28 and the headof the holddown bolt 5. The tubular spacer 28, insert 29, and washer 35are all vulcanized in position and embedded in the elastomer materialthere being a raised pad portion 36 of the elastomer material extendingapproximately one-half inch above the track plate 8 at the holddowncorners of the track plate 8. The raised vulcanized pad portions 36prevent corrosive contaminants from leaking into the holddown boltholes. In addition, the raised pad portion 36 of the elastomer materialfurther facilitates electrical isolation of the base plate from thetrack plate, as conductive fluids might otherwise tend to make anelectrical connection between the track plate and the base plate 4through the intermediary of the tubular spacers 28.

When the holddown bolts 5 are tightened down onto the washers 35, thetubular spacers 28 are placed in compression so as to form a rigidlateral restraining structure upstanding from the base plate 4. When thelateral forces on the track plate 8 are in one direction, such as F(FIG. 6) one bar portion 31 of the high compression strength insert 29takes the lateral forces in compression. More particularly, the insidebar portion 31 of one of the restraining inserts takes one-half of thelateral force on compression and the other half of the lateral force istaken in compression on the outside bar portion 31 of the otherrestraining insert 29. Conversely, when the lateral forces are in theopposite direction, such as F the outside bar portion 31 of one of therestraining inserts takes one half of the lateral restraining force andthe inside bar portion 31 of the other restraining insert 29 takes theother half of the lateral force. In a typical example, the inserts 29take 5,000 pounds of the lateral load in compression without producingundue lateral deflection of the rail 2.

What is claimed is:

1. In a rail fastener for fastening a track to a support structure andfor providing vibrational damping and electrical isolation between thetrack and the support structure:

base plate means for attachment to the underlying support structure;

track plate means for attachment to a track, said track plate meansbeing disposed overlaying said base plate means;

elastomer means interposed between said base plate means and said trackplate means fo supporting said track plate means from said base platemeans and for damping vibration of said track plate means and forelectrically insulating said base plate means from said track platemeans;

means for securing the track to said track plate means such that thetrack will overlie the track plate in a predetermined track region ofsaid track plate means;

means for restraining lateral displacement of said track plate meansrelative to said base plate means, said lateral restraining meansincluding, means upstanding from said base plate means on oppositelateral side of said track region of said track plate means forrestraining excessive lateral displacement of said track plate means,insert means interposed between an adjacent edge of said track platemeans and said upstanding lateral restraining means for taking incompression and transferring lateral forces on said track plate to saidupstanding lateral restraining means, said insert means having asubstantially higher compressive strength than that of said elastomermeans and being made of an electrically insulative material forelectrically insulating said lateral restraining means from said trackplate means.

2. The apparatus of claim 1 wherein said upstanding lateral restrainingmeans includes, a pair of tubular members upstanding from said baseplate means on opposite lateral sides of said track region of said trackplate means.

3. The apparatus of claim 2 wherein each of said tubular members iscoaxially aligned with respective apertures in said base plate means.

4. The apparatus of claim 3, including, threaded fastener means forsecuring said base plate means to the underlaying support structure,said fastener means passing coaxially through said tubular members andaligned apertures in said base plate means to take said tubular membersin compression against said underlying base plate means.

5. The apparatus of claim 4 wherein each of said tubular membersincludes at least one generally flat side facing a generally flat edgeportion of said track plate means, and wherein each of said respectivemeans includes a pair of flat sides one facing the adjacent flat side ofsaid tubular member and the other facing the adjacent flat edge portionof said track plate means.

6. The apparatus of claim 5 wherein said track plate means is aperturedwith a pair of rectangular openings coaxially aligned with said tubularmembers.

7. The apparatus of claim 1 wherein said elastomer means includes aplurality of voids therein for increasing the vibration damping of saidelastomer means.

8. The apparatus of claim 7 wherein said voids are elongated laterallyof a track, and are spaced apart along the direction of the track.

9. The apparatus of claim 7 wherein said base plate means is aperturedin registration with each of said voids.

1. In a rail fastener for fastening a track to a support structure andfor providing vibrational damping and electrical isolation between thetrack and the support structure: base plate means for attachment to theunderlying support structure; track plate means for attachment to atrack, said track plate means being disposed overlaying said base platemeans; elastomer means interposed between said base plate means and saidtrack plate means fo supporting said track plate means from said baseplate means and for damping vibration of said track plate means and forelectrically insulating said base plate means from said track platemeans; means for securing the track to said track plate means such thatthe track will overlie the track plate in a predetermined track regionof said track plate means; means for restraining lateral displacement ofsaid track plate means relative to said base plate means, said lateralrestraining means including, means upstanding from said base plate meanson opposite lateral side of said track region of said track plate meansfor restraining excessive lateral displacement of said track platemeans, insert means interposed between an adjacent edge of said trackplate means and said upstanding lateral restraining means for taking incompression and transferring lateral forces on said track plate to saidupstanding lateral restraining means, said insert means having asubstanTially higher compressive strength than that of said elastomermeans and being made of an electrically insulative material forelectrically insulating said lateral restraining means from said trackplate means.
 2. The apparatus of claim 1 wherein said upstanding lateralrestraining means includes, a pair of tubular members upstanding fromsaid base plate means on opposite lateral sides of said track region ofsaid track plate means.
 3. The apparatus of claim 2 wherein each of saidtubular members is coaxially aligned with respective apertures in saidbase plate means.
 4. The apparatus of claim 3, including, threadedfastener means for securing said base plate means to the underlayingsupport structure, said fastener means passing coaxially through saidtubular members and aligned apertures in said base plate means to takesaid tubular members in compression against said underlying base platemeans.
 5. The apparatus of claim 4 wherein each of said tubular membersincludes at least one generally flat side facing a generally flat edgeportion of said track plate means, and wherein each of said respectivemeans includes a pair of flat sides one facing the adjacent flat side ofsaid tubular member and the other facing the adjacent flat edge portionof said track plate means.
 6. The apparatus of claim 5 wherein saidtrack plate means is apertured with a pair of rectangular openingscoaxially aligned with said tubular members.
 7. The apparatus of claim 1wherein said elastomer means includes a plurality of voids therein forincreasing the vibration damping of said elastomer means.
 8. Theapparatus of claim 7 wherein said voids are elongated laterally of atrack, and are spaced apart along the direction of the track.
 9. Theapparatus of claim 7 wherein said base plate means is apertured inregistration with each of said voids.